test: migrate e2e to Playwright and component test to Vitest browser mode

Replace Cypress with Playwright for the end-to-end suite and drop
@shellygo/cypress-test-utils in favour of a hand-written MaputnikDriver
page object that keeps the fluent then(...).shouldX() assertion style
(now async). The InputAutocomplete component test moves to Vitest browser
mode using the Playwright provider.

- e2e/maputnik-driver.ts: driver + MaputnikAssertable over Playwright
- e2e/{fixtures,coverage,global-setup,global-teardown}.ts: test fixture,
  istanbul coverage collection, and nyc report generation
- playwright.config.ts / vitest.config.ts
- Code coverage preserved: dev server is istanbul-instrumented, per-test
  window.__coverage__ is merged via nyc into coverage/coverage-final.json
- CI: Cypress jobs replaced with Playwright; docker e2e runs against the
  container via E2E_NO_WEBSERVER
- Remove Cypress deps, config and support files; update docs and .nycrc

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -24,22 +24,22 @@ The project type checked and built with:
 npm run build
 ```
 
-To run the tests make sure that xvfb is installed:
+Install the Playwright browser (first time only):
 
 ```
-apt install xvfb
+npx playwright install --with-deps chromium
 ```
 
-Run the development server in the background with Vite:
+Then run the end-to-end tests (Playwright starts the dev server automatically):
 
 ```
-nohup npm run start &
+npm run test
 ```
 
-Then start the Cypress tests with:
+Run the unit and component tests with Vitest:
 
 ```
-xvfb-run -a npm run test
+npm run test-unit
 ```
 
 ## Pull Requests